Tool-free adjustable clean out assembly for a pump

ABSTRACT

A clean out assembly for a centrifugal pump, particularly, for example, a self-priming-type of centrifugal pump, is structured to provide easy adjustment of the clean out assembly and axial movement of a wear plate in proximity to the impeller of the pump without the need for tools to effect such movement of the wear plate and clean out assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional application claiming priority toprovisional patent application Ser. No. 60/707,006 filed Aug. 10, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to self-priming centrifugal pumps, and relatesspecifically to a clean-out assembly for a self-priming pump thatfacilitates access to the interior of the pump and axial adjustment ofthe wear plate relative to the impeller.

2. Description of Related Art

Self-priming centrifugal pumps are well-known and frequently used inindustries where processing fluids with entrained solids is required.Self-priming pumps, also known as trash pumps, are characterized ashaving a casing which houses a suction chamber and a separation chamberdivided by a wall or plenum. An impeller positioned in a volute sectionof the pump receives fluid from the suction chamber and delivers it bycentrifugal action into the separation chamber where it is eventuallyexpelled through an outlet.

The impeller of self-primer pumps are generally of the open type,meaning that the impeller has a rear shroud, but an open eye into whichfluid flows from the suction chamber. In order for the pump to operatemost efficiently, the impeller must be positioned as close as possibleto the wall of the volute casing of the pump to minimize recirculationand leakage of fluid out and around the impeller. To accomplish that, awear plate is typically positioned between the volute casing and theopen or suction side of the impeller. The wear plate is positioned invery close proximity to the impeller vanes to assure efficient pumpoperation.

As the pump is operated, especially in the processing of fluids withentrained solids, the vanes of the impeller and/or the wear plate canbecome worn down by the solids and the resulting gap or clearancebetween the impeller vanes and wear plate causes the pump to operatewith less efficiency. It then becomes necessary to adjust the distanceor clearance between the impeller and the wear plate to assure a closefit therebetween.

Pump manufacturers have dealt with this problem in the prior art byproviding various means by which the clearance between the impeller andthe wear plate can be adjusted as needed. In old prior art systems, anadjustment was provided for axial movement of the rotating assembly(i.e., impeller and drive shaft) relative to a stationary wear plate orpump casing. However, such adjustment means involved the need tocorrespondingly adjust the drive shaft relative to the motor, andinvolved other compensatory adjustments to structural elements of thepump.

In certain types of pumps, exemplified by self-primer pumps, a clean outassembly is provided which serves two essential purposes. First, theclean out assembly provides access to the eye of the impeller throughthe suction chamber and provides a convenient means for removing solidsor other debris that may have clogged the impeller. Second, the cleanout assembly has provided a supporting structure for the wear plate and,consequently, a means for adjusting the axial distance between the wearplate and impeller.

In presently known clean out assemblies having means for adjusting thewear plate, the adjustment means or devices are complicated, usuallyrequiring several adjustment and securement devices, and all requiretools for removing and/or adjusting the several elements to effect anadjustment of the wear plate. As a result, adjusting the wear plate canbe difficult and time consuming, and the several elements that comprisethe adjustment mechanism increase the cost of the pump.

Thus, it would be advantageous to provide a clean out assembly thatprovides adjustment of the wear plate, but which requires no tools toeffect the adjustment of the wear plate or to remove the clean outassembly for servicing of the pump, thereby also simplifying manufactureof the pump and reducing the cost of manufacture.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a clean out assembly for apump, particularly a self-primer-type centrifugal pump, is structured toprovide support for a wear plate and to provide a tool-free means fornot only axially adjusting the wear plate relative to the impeller ofthe pump, but to facilitate removal of the clean out assembly forservicing the impeller of the pump. As used herein, “tool-free” meansthat no tools are required to effect movement or adjustment of thedescribed elements of the clean out assembly and that such movement isachieved by using one's hand to effect such adjustment or movement.

The clean out assembly of the present invention generally comprises anend cover which provides support for a wear plate and is positioned tocover the access opening in a centrifugal pump axial to the eye of theimpeller. The end cover supports a wear plate that is positioned inclose proximity to the impeller when the end cover is secured in placewithin the pump casing. The end cover is attached is the pump casing bysecurement apparatus.

The end cover, and thus the wear plate, is axially adjustable relativeto the pump casing and the impeller by adjustment elements that operateseparately from the securement apparatus for attaching the end cover tothe pump casing and, in an especially suitable embodiment may be spacedfrom the securement apparatus. By providing adjustment elements operablyseparate from the securement means, axial adjustment of the wear plateis significantly simplified over conventionally-known clean outassemblies for pumps.

The adjustment elements comprise a threaded shaft that is threadinglypositioned through openings in the end cover. The adjustment elementsalso have a handle which can be turned by hand to effect adjustment ofthe end cover relative to the pump casing, and thus effect axialadjustment of the wear plate relative to the impeller. The securementapparatus for attaching the end cover to the pump casing are also eachprovided with hand nuts that enable tightening of the securementapparatus by hand. No tools are required to effect attachment oradjustment of the end cover relative to the pump casing, as isconventional in the prior art.

The simplified structures of the present clean out assembly enable axialadjustment of the end cover and wear plate without the need for tools,and enable axial adjustment without removal of any parts. Theconfiguration of the present clean out assembly effectively reduces themanufacturing and operating costs of the pump.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which illustrate what is currently considered to be thebest mode for carrying out the invention:

FIG. 1 is a perspective view of a prior art pump illustratingconventional structure for a clean out assembly;

FIG. 2 is a view in cross section of the prior art clean out assemblyshown in FIG. 1;

FIG. 3 is a perspective view of a pump illustrating the clean assemblyof the present invention; and

FIG. 4 is a view in cross section of the clean assembly of the presentinvention as shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

By way of comparison, a prior art clean out assembly 10 is illustratedin FIGS. 1 and 2 which comprises, in general, an end cover 12 and asupporting ring 14 spaced from the end cover 12 by a plurality ofstanchions 16. The supporting ring 14 provides a means for attachmentthereto of a wear plate 18, which is connected to the supporting ring 14by screws 20. The clean out assembly 10 fits into an opening 22 formedin the pump casing 24 so that the wear plate 18 is positioned adjacentthe impeller 25, as best seen in FIG. 2.

In the prior art pump of FIG. 1, the clean out assembly 10 is connectedto the pump casing 24 by a plurality of threaded studs 26 that extendthrough holes 28 formed in the end cover 12. The end cover 12 is securedin place by hand nuts 30 that tighten onto the threaded studs 26.

The means for adjusting the axial position of the wear plate 18 relativeto the impeller is also associated with the means for attaching the endcover 12 to the pump casing 24. Specifically, a threaded adjustmentmember 34 threads into each opening 28 in the end cover 12 and slipsonto the threaded stud 26. The adjustment member 34 has ahexagonally-configured head the corners of which engage with teethformed in a central opening 38 of a locking member 36. The opening 38 ofthe locking member 36 is sized to receive the head of the adjustmentmember 34.

The locking member 36 is normally bolted to the end cover 12 by thepositioning of a locking bolt 40 and washer 42 through an opening 44 inthe locking member 36. The locking bolt 40 then threads into an opening46 in the end cover 12. When the axial position of the wear plate 18 isto be adjusted (i.e., the axial position of the clean out assembly is tobe adjusted relative to the pump casing 24), the hand nut 30 must firstbe removed from the threaded stud 26. The locking member 36 is thenremoved from the end cover 12 by using a first tool to loosen and removethe locking bolt 40 and nut 44.

Each adjustment member 34 is then rotated a selected amount to move theend cover 12 toward the pump casing 24. A tool different from the toolused to remove the locking bolt 40 is used for that process. Once theadjustment members 34 are rotated the desired amount, the locking member36 is replaced about the head of the adjustment member 34 and is lockedin place by securement of the locking bolt 40 into place. Each of thesesteps requires various tools for effecting the adjustment, and theadjustment involves manipulation of several structural elements, all ofwhich results in time-consuming and costly servicing and added cost formanufacturing of the pump.

The clean out assembly 50 of the present invention, shown in FIGS. 3 and4, solves the problems encountered with prior art clean out assembliesby providing a simplified and tool-free means for attaching the cleanout assembly to the pump casing and for effecting adjustment of the wearplate. Further, the clean out assembly of the present invention providesmeans for attachment of the end cover to the pump casing which isseparate from the axial adjustment structure, thereby eliminating theneed to remove structural elements associated with attachment of the endcover as is required in the prior art.

The clean out assembly 50 of the present invention comprises an endcover 52 and a supporting ring 54 to which a wear plate 56 is attachedby some means, such as bolts 58. The supporting ring 54, and thus thewear plate 56, is spaced from the end cover 52 by a plurality of spacercolumns 60. The clean out assembly 50 fits into an opening 62 in thepump casing 64 in the conventional manner to position the wear plate 56in very close proximity to the impeller 61, as best seen in FIG. 4.

The end cover 52 of the present invention is secured adjacent theshoulder 66 surrounding the opening 62 in the pump casing 64 bysecurement apparatus comprising a plurality of threaded stud bolts 68that extend through openings 70 in the end cover 52. A threaded hand nut72 is attachable to each stud bolt 68 providing a means for tighteningthe end cover 52 to the pump casing 64.

Axial adjustment of the wear plate 56 in the present invention iseffected by providing two or more adjustment elements 78 that comprise athreaded shaft 80 and a handle 82. The threaded shaft 80 of theadjustment element 78 is threaded through a threaded opening 84 in theend cover 52. As best seen in FIG. 4, the adjustment element 78 is setso that the terminal end 86 of the threaded shaft 80 seats against theshoulder 66 of the pump casing 64. As will become apparent for axialadjustment purposes, the end cover 52 is initially positioned relativeto the shoulder 66 of the opening 62 in the pump casing 64 such that aspace 88 is provided between the shoulder 66 and the end cover 52.

When adjustment of the wear plate 56 is required (i.e., when the wearplate 56 needs to be brought into closer proximity to the impeller 61),the hand nuts 72 on the stud bolts 68 are loosened slightly by hand toallow movement of the end cover 52. The handle 82 of each adjustmentelement 78 is then rotated by hand to effect movement of the end cover52 in a direction toward the pump casing 64, and thus effect axialmovement of the wear plate 56 toward the impeller 61. Movement of theend cover 52 is accomplished by the fact that the threaded shaft 80 ofthe adjustment elements 78 are threaded into the threaded openings 84 inthe end cover 52; consequently, rotation of the handles 82 causes theend cover 52 to move in a direction toward the impeller 61.

Once the wear plate 56 is adjusted to the desired point of proximity tothe impeller 61, the hand nuts 72 are then turned by hand to tighten theend cover 52 again to the pump casing 64. The adjustment elements 78 ofthe invention are structured with self-locking threads that lock theadjustment elements 78 into place after movement. However, a lockingelement of known structure may also be employed to secure the adjustmentelements 78 in place. Indicia 90 may also be provided on the adjustmentelements 78 to calibrate the amount by which the axial adjustment ismade.

It can be appreciated from the foregoing disclosure that the clean outassembly of the present invention provides an improved and simplifiedmeans of securing the clean out assembly to the pump casing andeffecting axial adjustment of the wear plate relative to the impeller,while reducing the costs of manufacture and operation of the pump. Thestructure, configuration and placement of the adjustment elements mayvary from that illustrated and described herein. For example, whileillustrated and described herein as being spaced from the stud boltsthat secure the end cover to the pump casing, the adjustment elementsmay be located in proximity to the stud bolts, but operate separatelyfrom the stud bolts in a manner similarly described herein for effectingaxial movement of the end cover, and without the need for tools.Accordingly, reference herein to particular details of the clean outassembly of the present invention are by way of example, and not by wayof limitation.

1. A centrifugal pump having a clean out assembly, comprising: a pumpcasing housing an impeller and having an opening oriented axially to theeye of the impeller for receiving a clean out assembly; a clean outassembly having an end cover attached to and spaced from a wear platefor positioning in proximity to said impeller; securement apparatus forsecuring said clean out assembly to said pump housing; and at least twoadjustment elements positioned on said end cover for providing tool-freeaxial adjustment of said wear plate relative to said impeller, saidadjustment elements being separately operable from said securementapparatus such that said adjustment elements effect axial movement ofsaid wear plate without removal of said securement apparatus from saidend cover.
 2. The centrifugal pump of claim 1 wherein said adjustmentelements are configured with handles for effecting tool-free movement ofsaid adjustment elements for axial adjustment of said end cover.
 3. Thecentrifugal pump of claim 2 wherein said adjustment elements arepositioned between said end cover and said pump casing.
 4. Thecentrifugal pump of claim 3 wherein said adjustment elements furthercomprise a threaded shaft threading received through said end cover. 5.The centrifugal pump of claim 1 wherein said adjustment elements furthercomprise indicia for determining the amount of axial adjustment made tosaid end cover.
 6. The centrifugal pump of claim 1 wherein saidsecurement apparatus further comprises stud bolts connected to said pumpcasing which are receivable through corresponding openings formed insaid end cover, and further wherein said securement apparatus comprise ahand nut for too-free adjustment of said securement apparatus.
 7. Acentrifugal pump having a clean out assembly, comprising: a pump casinghousing an impeller and having an opening oriented axially to the eye ofthe impeller for receiving a clean out assembly; a clean out assemblyhaving an end cover attached to and spaced from a wear plate; aplurality of threaded studs securing said end cover to said pump casingby means of a hand bolt connected to said threaded studs; adjustmentelements each comprising a threaded shaft for threaded attachmentthrough said end cover and a handle formed to said threaded shaft foreffecting tool-free rotation of said threaded shaft by hand, saidthreaded shaft being positioned in contact with said pump casing.
 8. Thecentrifugal pump of claim 7 further comprising indicia for determiningthe amount of axial adjustment of said end cover.